Skinning broken on models that have more than one skeleton

[tfili]

I've tried to convert a few models I'm ending up with some unexpected results.

You can find the models here: https://drive.google.com/file/d/1YeuFp48HwEqMhz4GA0rD2l-U7V-xfcYJ/view?usp=sharing

I've tried using PBR and Materials Common and both have issues. I end up with missing textures on Cesium Man and incorrect fully transparent materials in the Milk Truck.

Also, the animations in Cesium Man is broken as well. Other animations I've tried have worked, so it may have to do with skinning, but I'm not sure.

[lasalvavida]

Hi @tfili

I've tried using PBR and Materials Common and both have issues. I end up with missing textures on Cesium Man and incorrect fully transparent materials in the Milk Truck.

A few small issues from the transparency implementation that I just merged to master. These should be fixed in #221.

Also, the animations in Cesium Man is broken as well. Other animations I've tried have worked, so it may have to do with skinning, but I'm not sure.

The Cesium Man model from the sample models repository converts properly. The two main differences seem to be:

• The node transforms are translation+rotations as opposed to matrices
• Multiple skeletons on the instances controller instead of a single skeleton

The COLLADA looks okay in blender, so it does seem to be a converter issue, just not sure what particularly yet.

[lasalvavida]

Multiple skeletons on the instances controller instead of a single skeleton

It's probably this, right now we only write the first skeleton since glTF can't have more than one per node. I think we'll need to split the skeletons out as children with a new root node in this case.